A collection of new evidence in a little-known double-murder case may exonerate a man on Florida's death row. The development comes at a time when Florida is moving to accelerate the pace of executions.

In a quiet legal battle waged last month in a courtroom just up the road from Tampa Bay, attorneys for convicted double-murderer Clemente Aguirre-Jarquin's asked a judge to grant him a new trial.

Aguirre-Jarquin was convicted of stabbing to death his two next-door neighbors, Cheryl Williams and her mother, Carol Bareis, in 2004. The new evidence not only casts doubt on his guilt, the attorneys say, it points to Williams' daughter, Samantha, as the real killer.

Seminole County Circuit Judge Jessica Recksiedler will rule on their request sometime this month. Regardless of the outcome, though, the case is one that raises questions about the efficiency and fairness of the death penalty — questions that are especially important in the wake of the Florida Legislature's recent passage of the Timely Justice Act, an effort to speed up executions.

"I think (Aguirre-Jarquin) is very lucky that it only took six years to prove his innocence and not 15 or 20," said Nina Morrison, senior staff attorney for the Innocence Project, which assisted with the case's DNA testing. "Under the provisions of the Timely Justice Act, he might not be alive today."

Aguirre-Jarquin, 33, was sentenced to die in 2006.

State prosecutors maintain that he sneaked into the mobile home at 121 Vagabond Way in Altamonte Springs just before 6 a.m. on June 18, 2004. Inside, he stabbed Bareis twice and Williams 129 times with a kitchen knife. He then ran back to his home.

When deputies questioned him, Aguirre-Jarquin first denied knowledge of the murders. Later, he admitted that he had visited the home early that morning to ask if they had beer. He came across Williams' body and tried to revive her, he said. After he realized she was dead, he stepped further inside and found Bareis. He spotted the knife and picked it up, fearing the killer might still be there, he said. He ran home and tossed the knife in the grass.

Deputies didn't buy it, but Aguirre-Jarquin never wavered in his claim of innocence. He said he didn't report the crime because he was an undocumented immigrant from Honduras and feared being deported.

It wasn't until 2010 that doubts about his guilt became apparent.

That year, attorneys Maria Deliberato and Marie-Louise Samuels Parmer of the Capital Collateral Regional Counsel, a state agency that defends death row inmates, ordered DNA testing on 84 pieces of evidence found at the crime scene. None had been tested before. When the results came back, most of the DNA matched Bareis and Williams. None matched Aguirre-Jarquin.

A defense crime scene expert, who testified in the court hearing last month before Judge Recksiedler, said the stains on Aguirre-Jarquin's clothing are consistent with his account of having touched the bodies, but not with his having done the stabbing.

A medical examiner hired by the defense also testified that the original autopsy report was wrong in stating the victims died at 6 a.m. They actually died at least three hours earlier, the expert said.

That's important because Aguirre-Jarquin said he didn't enter the mobile home until 6 a.m.

Attorneys also tested eight small blood droplets found at the scene that did not match Aguirre-Jarquin. The stains, which an expert said were fresh, matched Samantha Williams.

The attorneys looked at Samantha's background. They found she had struggled with mental illness and took anti-psychotic medication. She also had a history of trouble with the law. By her own estimation, Williams said in court last month, she has been detained 60 times since age 14 under Florida's Baker Act for being considered a threat to herself or others.

In one incident in August 2010, police were summoned after Williams, then 27, threatened to set herself on fire, according to a sheriff's report. A deputy later found her lying on a comforter that had been burned. The deputy talked to a neighbor, who told him that Williams had stopped taking her medication.

"I spoke with a neighbor who stated that Samantha had been refusing to take her 'psychotic' medication and has been saying that 'demons' are in her head and caused her to 'kill' her family," the deputy's report read.

In another incident in 2007, video from inside a police cruiser captured Williams banging her head against the car's roof while handcuffed in the back seat. She cried and screamed and cursed.

"Do you understand that they died for me," she wailed.

Testifying at last month's hearing, Samantha Williams said she loved her mother and grandmother. She admitted to struggling with mental illness, getting into violent fights with her mother, and even to arguing with her the night before the murders. But she denied she was a killer.

The blood stains, she said, could have been from any of the numerous times she hurt herself at home, like the time she stabbed a knife through a table and cut off part of her own finger.

Prosecutors stand by their case against Aguirre-Jarquin. They say the blood on his clothing, among other evidence, proves that he is a killer.

"The State Attorney's Office is pleased that all of the evidence was presented in court," Phil Archer, the state attorney for Seminole County, said in a statement. "We believe the defendant was very well represented by counsel and now we await the judge's ruling. Any further determination of how to proceed will be made at that point."

Morrison, of the Innocence Project, said the new evidence adds up to a case of actual innocence, a rarity among death row inmates. She said police and prosecutors developed a theory of the crime early on and rushed to judgment.

"I think Clemente's case is a sobering reminder that innocence doesn't prove itself," she said. "A lot of people think we don't send innocent people to death row anymore, and that's just not the case."

In April, Florida legislators passed what has been dubbed the Timely Justice Act. The bill, sponsored by Rep. Matt Gaetz, R-Fort Walton Beach, is designed to speed up executions for death row inmates. Among other things, the act sets deadlines for death row inmates to file appeals and requires the governor to sign death warrants within a certain time after appeals have been completed.

Critics of the law, including some previously exonerated death row inmates, have said it creates more room for error in capital cases. For anti-death penalty advocates Florida is of special concern, too, since the state issued more death sentences last year that any other.

"I think that this case is a perfect example of why it's important to have a legitimate post-conviction process," said Parmer, one of Aguirre-Jarquin's attorneys. "If anything, (the Timely Justice Act) makes it more of a risk that an innocent person could get executed."